Car Rental Claim Credit never charged...need help

Ok,

So I rented a car with my travel MC and the area I was visiting had a hailstorm, so the car rental company filed a claim. I submitted all paperwork to my ccard and they paid the claim, to the tune of $3500....BUT, the car rental company NEVER CHARGED ME more than the cost of the rental...so now I have a $3400 credit on the card.

What do I do?

I called the card because I'm not about to start using the card only to have them come back and drop $3500 back onto the card to offset the mistake. The lady on the phone said, "oh, why did you call me? The call is being recorded so there is only so much I can say, but we would never check to see if you've been charged." I said thank you, have a nice day and hung up.

What do I do now? Call them back and ensure it gets rectified? Enjoy the $3500 credit until they fix the mistake? My concern with using the card is that I would never have a payment due until I used up the $3500...so then when they charge me back the $3500, I'll have that to pay off. Thoughts?